Vacancy distribution measurements in CZ Si crystals grown by different pulling rate

Vacancy concentration distribution is estimated by measuring deep levels in duced by N-2-vacancy complexes in the wafers which are prepared from Si cry stals grown by different pulling rate. Tt is found that the vacancy concent ration is very low inside the OSF-ring and a little low in the ring region. Two kinds of the vacancy density profiles are observed in the specimens wi thout the OSF-ring which are prepared from Si crystals grown by fast (1.4 m m/mm) and slow (0.4 mm/mm) pulling rate: one is a gradual and the other is a abrupt zigzag profile. We interpret the gradual profile is caused by macr oscopic density change of the octahedral void defects and the abrupt variat ion is accompanied with the growth striation. (C) 1999 Elsevier Science B.V . All rights reserved.